Characterization and measurement of stone engravings

Engraving by waterjet and laser processing is an emerging stone process for product identification and traceability (characters or codes) and for decoration (inlay). The main characterization and measurement issues for the optimization of the engraving process and for product inspection are discussed. Stylus measurement is not suitable for accessibility and for the very steep surfaces, so an optical profilometer and a specific setup, has been developed. A special measurement method and algorithm is proposed to define the main geometric features of engravings at microscopic level. Based on our analysis the conventional engraving width and several quality measures have been defined.